There has been an increasing interest in the monitoring of various vital body signs for a number of reasons.
There is an interest in monitoring the position of the human body for a number of reasons.
A particular issue is sleep disorder. Sleep disorder is a very widespread phenomenon. About 40% of American adults suffer from some kind of sleep disorder while about 70 million Americans are chronically sleep deprived. Accordingly, measurement of sleeping quality and sleep disturbances is required. As well as vital parameters such as heart rate, respiration rate and body temperature, body position is an important parameter in such measurements.
The measurement of body position can also be important to detect changes in body position where this is needed for medical reasons, for example for people who are at risk of developing a decubitus sore or ulcer.
It is further beneficial if the measurement of body position should be unobtrusive. Sensors should in particular be unobtrusive, unrestrictive and comfortable for the user.
A particular system for detecting changes in body posture using an electrocardiogram (ECG) is described in U.S. Pat. No. 5,865,760. The ECG is analyzed to detect artefacts caused by changes in body posture.